Time-dependent variations in urine output after renal transplantation

Abstract

Introduction. Diuresis begins soon after renal transplantation. Although controversial, early post kidney transplant urine volume may correlate with favorable short- and long-term allograft survival. The aim of the present study was to examine the potential changes in urine volume within the first 6 months after renal transplantation. Methods. In a prospective study, the first month serum creatinine level and daily urine volume were measured at 24 and 48 hours, and at 1 month after renal transplantation in patients with stable kidney function without the evidence of allograft rejection (n = 54). Fifteen patients were also followed for their urine output at least 6 months post kidney transplantation. Data are expressed in mean values SD. Statistical analysis was performed by SPSS version 13.0 using ANOVA. Correlation between continuous variables was performed using the Pearson test. The P value was set at .05. Results. The mean age of the renal allograft recipients was 35.5 +/- 12.1 years with a male to female ratio of similar to 1.3. The mean first month serum creatinine was 1.26 +/- 0.4 mg/dL. The mean urine outputs were 10.06 +/- 5.89, 5.45 +/- 3.05, and 3.44 +/- 1.25 L at 24 and 48 hours and 1 month post renal transplantation. Those patients who were followed for 6 months post transplant (n = 15) were observed to have a mean urine volume of 3.20 +/- 1.24 L at the end of this period. This trend showed that urine volume steadily decreased from 24 and 48 hours to 1 month after renal transplantation (P <.05). However, urine volumes were rather comparable at one month and 6 months after transplantation (P >.05). A positive correlation was found between the first-month serum creatinine and the urine volume at one month (r = 0.302 and P =.035). Conclusion. Although urine volume showed considerable variation early after renal transplantation, it stabilized by 1 month after transplantation, which was also positively correlated with the first-month serum creatinine. Moreover, we concluded that in stable patients, the final urine output was related to early graft function.